Gut health
Dr. Will Bulsiewicz
- 75% Trust Score
- 915 claims analyzed
- 753K followers
- 665 verified · 239 questionable · 11 debunked
Is Dr. Will Bulsiewicz trustworthy?
Dr. Will Bulsiewicz has a Verify Influencers Trust Score of 75 out of 100, which we classify as generally reliable. Of the 915 health claims we analyzed, 665 are verified by peer-reviewed research, 239 are questionable, and 11 are debunked.
Why this score
Dr. Will Bulsiewicz, MD, MSCI, is a board-certified gastroenterologist with over two decades of clinical experience, specializing in gut health, microbiome optimization, and plant-based nutrition as a lifestyle medicine pioneer. A graduate of Georgetown University School of Medicine and Northwestern University, he served as Chief Resident at Northwestern Memorial Hospital and Chief Fellow at UNC Hospitals, authoring more than 25 peer-reviewed publications. He is a New York Times bestselling author of *Fiber Fueled* and *The Fiber Fueled Cookbook*, founder of the supplement company 38TERA, and U.S. Medical Director for ZOE.
Dr. Will Bulsiewicz's most repeated claims
- Verified (74/100) — Exposure to natural morning sunlight within the first hour of waking can increase the morning cortisol spike by 50%, helping to regulate the circadian rhythm and improve gut health. (Sleep & Recovery) source
- Verified (75/100) — Aim for a minimum of 30 different varieties of plants per week (including fruits, vegetables, whole grains, seeds, nuts, and legumes) to optimize microbiome diversity. (Gut Health & Microbiome) source
- Verified (72/100) — Aim to consume 30 different types of plants per week to maximize gut microbiome diversity, which is the single strongest determinant of a healthy gut and clear skin. (Gut Health & Microbiome) source
- Verified (83/100) — Green (unripe) bananas are a powerful natural prebiotic because they contain high levels of resistant starch that feeds beneficial gut bacteria. (Gut Health & Microbiome) source
- Verified (76/100) — Consuming six servings of fermented foods daily (like sauerkraut, kimchi, or kefir) can significantly increase microbiome diversity and reduce 19 different inflammatory markers in just 10 weeks. (Gut Health & Microbiome) source
- Verified (72/100) — Chronic stress is as damaging to the gut microbiome as a poor diet, as it can alter the gut barrier and lead to systemic inflammation and 'leaky gut'. (Gut Health & Microbiome) source
- Verified (78/100) — 70% of the human immune system is located in the gut, separated from the microbiome by a single layer of cells, making gut health the primary determinant of immune function. (Gut Health & Microbiome) source
- Verified (72/100) — The gut microbiome is 'nocturnal' and requires a period of rest; eating after dark or late at night disrupts its natural repair cycle and immune function. (Gut Health & Microbiome) source
- Verified (76/100) — The G.R.O.W.T.H. protocol for food intolerances involves: Genesis (root cause), Restrict (temporary elimination), Observe (symptoms), Work it back in (reintroduction), Train your gut (escalation), and Holistic health. (Gut Health & Microbiome) source
- Verified (75/100) — Aim for 14 grams of fiber for every 1,000 kilocalories consumed per day as a personalized target for optimal microbiome support. (Gut Health & Microbiome) source
Verified claims
- Verified (74/100) — Exposure to natural morning sunlight within the first hour of waking can increase the morning cortisol spike by 50%, helping to regulate the circadian rhythm and improve gut health. (Sleep & Recovery) source
- Verified (75/100) — Aim for a minimum of 30 different varieties of plants per week (including fruits, vegetables, whole grains, seeds, nuts, and legumes) to optimize microbiome diversity. (Gut Health & Microbiome) source
- Verified (72/100) — Aim to consume 30 different types of plants per week to maximize gut microbiome diversity, which is the single strongest determinant of a healthy gut and clear skin. (Gut Health & Microbiome) source
- Verified (83/100) — Green (unripe) bananas are a powerful natural prebiotic because they contain high levels of resistant starch that feeds beneficial gut bacteria. (Gut Health & Microbiome) source
- Verified (76/100) — Consuming six servings of fermented foods daily (like sauerkraut, kimchi, or kefir) can significantly increase microbiome diversity and reduce 19 different inflammatory markers in just 10 weeks. (Gut Health & Microbiome) source
Debunked claims
- Debunked (33/100) — The 'GROWTH' acronym for healing the gut stands for: Genesis, Re-train, Optimize, Wide variety, Timing, and Holistic healing. (Gut Health & Microbiome) source
- Debunked (22/100) — In a randomized trial, an 8-hour eating window (Time-Restricted Eating) reduced Crohn's disease activity by 40% and cut abdominal pain in half over 12 weeks. (Gut Health & Microbiome) source
- Debunked (39/100) — Morning cold showers help kickstart the body's cortisol awakening response. (Cold & Heat Therapy) source
- Debunked (37/100) — Dr. Bulsiewicz incorporates a 'weighted baton' or mallet into his walks, performing torso twists and overhead movements to engage the core and upper body. (Exercise & Fitness) source
- Debunked (38/100) — Sprouting green peas in total darkness for 6 days maximizes the production of the DAO (diamine oxidase) enzyme, providing 77% more DAO than expensive pig-kidney-derived supplements. (Gut Health & Microbiome) source
Products Dr. Will Bulsiewicz promotes
Frequently asked questions
- What is Dr. Will Bulsiewicz's trust score?
- Dr. Will Bulsiewicz has a Verify Influencers trust score of 75 out of 100, based on analysis of 915 health claims against peer-reviewed scientific research.
- Is Dr. Will Bulsiewicz trustworthy for health advice?
- Dr. Will Bulsiewicz has a Verify Influencers Trust Score of 75 out of 100, which we classify as generally reliable. Of the 915 health claims we analyzed, 665 are verified by peer-reviewed research, 239 are questionable, and 11 are debunked.
- How many claims has Dr. Will Bulsiewicz made?
- We have analyzed 915 health claims from Dr. Will Bulsiewicz across YouTube, social media, podcasts, and their website.
Scores follow a fixed rubric and are re-checked on a rolling cycle. How we score and how to request a correction. Last updated 2026-05-17.
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